双倒易边界元法应用于预测三维势流管道和消声器声学特性

将双倒易边界元法应用于预测具有三维势流存在时管道及消声器的声学特性,阐述了其基本原理与数值过程。与传统边界元方法相比,该方法考虑了声学控制方程中气流马赫数二阶小量的影响,因此适用于具有较高马赫数亚音速流的情况。使用双倒易边界元法预测有气流存在时管道和变截面膨胀腔的四极参数,并与一维解析解和传统边界元法结果进行了比较,从而验证了该方法的正确性。利用双倒易边界元计算并分析了不同结构类型消声器的传递损失,结果表明,三维流对复杂结构的消声器声学性能的影响是不可忽略的。PACS数:43.20,43.

Application of dual reciprocity boundary element method for prediction of acoustic characteristics of ducts and silencers with three-dimensional potential flow

The Dual Reciprocity Boundary Element Method (DRBEM) is applied to predict the acoustic characteristics of ducts and silencers with three dimensional potential flow, and the basic principle and numerical procedure of the proposed method are introduced. Compared to the Conventional Boundary Element Method (CBEM), the DRBEM takes into account the second order terms of Mach number of flow in the acoustic governing equation, so it is suitable for the cases with higher Mach number subsonic flow. The four-pole parameters of a duct and a varying cross-sectional area expansion chamber are predicted with the DRBEM, and the predictions are compared with the one dimensional analytical solutions and the CBEM results. The comparisons showed that the present method is valid. Transmission loss of silencers with different structure was also predicted with the DRBEM. The results showed that the influence of the three dimensional flow on the acoustic characteristics of silencers with complex structures is not negligible.